Crack identification in a rotor

A finite element (FE) model, which is based on transfer matrix analysis and local flexibility theorem, is introduced for crack identification of a static (non-rotating) rotor with an open crack. Through numerical simulation, the effects of the location and depth of the crack on the mode shapes and the changes in the eigenfrequencies of the cracked rotor are investigated, and the ratio of the changes in the first two eigenfrequencies is obtained for cracked rotor with different slenderness ratio. A crack identification algorithm that makes use of the translations of the first mode at two symmetric points and the changes in the first two eigenfrequencies to estimate the crack location and depth on the rotor is proposed, and an illustrative example demonstrates the availability and validity of the proposed algorithm.